Door latch mechanism



NOV. 19, 1940. F KAISER 2,222,411

DOOR LATCH MECHANISM OriginalV Filed July ll, 1939 za i' I 5? 5f y @f5/f@ j? f (3% ff S ff f? f L I 5 K BY a i W ATTORNEY.

Patented Nov. 19, 1940 -UNITED NSTATES PATENT oFFlcE lnfma original application July ll, 1939, serial No. 283,749. Divided and thisapplication December 6, 1939, Serial No. 307,763

4 Claims. (Cl. 292-465) This invention relates to improvements in door latch mechanism; this application being a `division of subject matter disclosed in my copending application Serial No. 283,749, flied July 11, 1939,

which has matured into Patent No. 2,188,149 of Jan. 23, 1940. l

This invention has for an object to provide a novel improved latch mechanism of the kind which is contained within a tubular or cylindrical casing mortised into a door body; said latch l thereof by the knob spindle means is smoothly and easily attained with a minimum otresistance, and whereby the latch mechanism is more eiliciently yieldably supported in latching position, as well as quickly returned to latching position after releasing manipulation.

Other objects of this invention, not at this time more particularly enumerated, will be understood from the following detailed description of the same.

I' `30 An illustrative embodiment of the invention is shown in the accompanying drawing, in which:

Fig. 1 is a fragmentary outside face view of a door equipped with the novel latch mechanism of this invention; Fig. 2 is a. vertical cross section,

'35 taken on line 2-2 in Fig. 1; Fig. 3 is a longitudinal section taken on llille 3-3 in Fig. 2, but drawn on an enlarged scale, this view showing lthe normal projected position of the'door latch;

and Fig. 4 is a view similar to that of Fig. 3, but

showing the door latch retracted.

Similar characters of references are employed in the above described views, to indicate corresponding parts.

Referring to the drawing,y the reference character I0 indicates a door to be served by the novel latch mechanism. Mounted in a mortised opening 'I|, extending inwardly into the door body from its freeend, is a cylindrical casing. This casing is longitudinally divided into two half sections I2 and I3 which are suitably secured together, one of which, as e. g. the section I2, is provided with an anchoring plate or ilangeportion I4, adapted to be countersunk in the door body edge and secured'thereto by screws (not 5:5 shown) in the usual manner, thus retaining the casing in operative assembled relation to said door body. Said anchoring lplate or ilange portion I4 is provided with an opening l5 aligned with the interior of the casing, and through which the chamfered latch nosing I6 of the latch i mechanism is normally outwardlyv projected. Said latch nosing I8 is carried by a latch plate Il, which is suitably slidably supported in the forward interior portion of the casing. Said latch plate Il is formed with laterally spaced 10 rearwardly directed longitudinal legs I8 which straddle a stationary abutment member I9, which is preferably formed as an integral part of the casing section I2. n Extending rearwardly from one of the latch plate legs I8 is a tail-piece 20 1I having at its extremity an upstanding retractor lug 2|.r Said latch plate I1 is yieldably urged ,forwardly to latch nosing projecting position by a compression spring 22 engaged between the same and said abutment member I9; said latch 20 plate having a keeper lug 23 forl seating the end of the spring 22 which engages the same.

'I'hecasing sections |2|3 are provided with laterally aligned transverse bearing portions 2l in which are respectively journaled the .opposite 25 ends of the journal hub 25 of a rotary cam piece which provides oppositely and radially extending cam arms 28. y

Longitudinally slidable in the rearward interior portion of the casing is a pull-plate 2l hav- 30 ing rearwardly extending laterally. spaced legs 28 adapted to straddle said hub 25 of the cam piece. Saidrlegs 28 are each provided, adjacent their extremities, with oiset retractor lugs 29 respectively engageable by the respective cam 38 arms 28 of said cam piece. At its forward end, said pllll-plate 21 is provided with a longitudinally extending offset pull-tongue 30. This pulltongue is provided, adjacent to its free end, with an upstanding thrust lug 3|. 'I'lle interior of the 4 casing section I2 is suitably formed to provide a guiding slideway 32, for said pull-tongue30. Pivotally mounted on a suitably, located fulcrum stud 33, with which said casing section I2 is provided, is a transversely disposed latch plate actuating lever 34 having a thrust nosing 35 at its free end to operatively' engage the retractor lug 2| of the latch plate tail-piece 20; said lever being operatively engaged, at a point intermediate 50 its fulcrum and free end, by said pull-plate thrust lug 3|, whereby a minimum actuatingmovement of said pull-plate'is compounded by and transmitted through said leverk 34 to effect a'maximum latch plate movement adequate to fully retract the latch-nosing I3 when the latch mechanism is actuated.

The pull-plate v21 is yieldably maintained in forwardly moved normal initial position by means 5 of a pair of compression springs 36, which are positioned against the rearward end wall of the casing, with their forward ends engaged respectively With the ends.. of the respective legs 23 of said pull-plate 21; the latter parts having seating bosses 31 to engage and hold said springs in operative relation thereto. By reason of the pro-- vision of said springs 33 to directly thrust upon and forwardly move said pull-plate 21, a yieldable forwardly thrusting force auxiliary to that exercised by the latch-plate spring 22 is furnished, whereby not only is a better balancing of the combined action of the moving parts of the latch mechanism attained. but the use of a less still and more smoothly operating latch plate spring is possible, and consequently a smoother and easier action of the latch mechanism as a whole is obtained.

The means for manipulating the above described latch mechanism'comprises, a knob spindle means 33 of substantially polygonal cross sectional shape to extend through the correspondingly shaped axial opening 33 of the rotatable cam piece 25-26 from one side of the door to the other. An exterior knob is operatively connected with the knob spindle means 33 at one end thereof. and an interior knob 40' is operatively connected with said knob p at the other end thereof.

Thev novel latch mechanism is optionally actuated by turning the spindle means 38 by either the exterior knob 40 or the interior knob 40', as the case may be. Turning of the spindle means 33 operates to rotate the cam-piece 2l to engage one or the other oi its cam arms 26 (as 4Q the case may be) with a corresponding retractor lug 29 oi the pull-plate 21, whereby the latter is retracted against the thrust of the springs 33.

The rearward movement of said pull plate 21 moves the thrust lug 3| against the lever 34, thereby swinging the latter rearward so as pro duce, through the engagement of the lever nos- 1 mg :s with the recraetor lug 2| of the laten` i plate I1, a relatively greater rearward sliding movement of said latch plate, whereby the latch 5o nose i6 is retracted to door releasing position.

` .Owing to the form of the pull-plate 21 having the spaced legs 28 which straddle the cam-piece 25, and the provision of the two compression Q springs 36 which respectively vthrustingly bear 65 against the extremities of the respective pullplate legs 28, a straight; line and smoothly bal'- anced movement of the pull-plate is assured, so

i that canting or cooking of the latter with rub- 1 bing and resultant frictional obstruction to free and easy movement thereof is avoided. As a consequence of this the relative movements of the latch mechanism parts are smoothly and easily t attained with a minimum of resistance, so that the latch mechanism works with a so-called o5 "soft action, and so as to assure eiiicient action of the same in its door closing and latching operation.

Since changes could be made in the above described latch mechanism, as well as in the details 70 of the construction thereof, without departing from the scope of my invention as defined in the following claims, I do not intend to limit the invention to the exact arrangement and construction of the devices and parts as hereinabove de- 75,y scribed and as shown in the drawings, said despindle means scription and showing being intended to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In door latch mechanism, a cylindrical casing adapted to be mortised into the free marginal edge portion of a door to be served by said latch mechanism, a cam piece rotatively mounted across said casing for operative engagement by door knob spindle means, a latch plate longitudinally slidable in said casing and provided with a latch nose for.projection from the outer end of said casing, springmeans for yieldably retaining said latch plate in latch nose projecting position, a longitudinally slidable pull plate behind and in longitudinal alignment with said latch plate, said pull plate having means engageable by said cam piece for retracting the same upon operation of the latter, said casing having a xed abutment intermediate said latch plate and pull plate to support said latch plate projecting spring means,I independent spring means for yieldably retaining said pull plate in forwardly moved normal position, and means intermediate said pull plate and said latch plate for transmitting operative movement of the former to the latter.

2. In door latch mechanism, a cylindrical casing adapted to be mortised into the free marginal edgey portion of a door to be served by said latch mechanism. a cam piece rotatively mounted across' said casing for operative engagement by door knob spindle means, a latch plate longitudinally slidable in said casing and provided with a latch nose for projection from the outer end of said casing, spring means for yieldably retaining said latch plate in latch nose projecting position, a longitudinally slidable pull plate behind and in longitudinal alignment with said latch plate, said pull plate having means engageable by said cam piece for retracting .the same upon operation of the latter, said casing having a fixed abutment intermediate said latch plate and pull plate to support said latch plate projecting spring means, independent spring means for yieldably retaining said pull plate in forwardly moved normal position, and means intermediate said pull plate and said latch plate fior transmitting operative movement of the former to the latter, said latter means comprising a pivoted lever arm, retractor means on said latch plate engageable by the free end portion of said lever arm, and means carried by said pull plate to engage said lever arm intermediate its pivoted and outer free end portions.

3. In a door latch mechanism, a cylindrical casing adapted to be mortised into the free marginal edge portion of a door to be served by said latch mechanism, a cam-piece rotatively mounted across said casing for operative engagement by door knob spindle means, a spring projected latch plate longitudinally slidable in said casing and provided with a latch nose for projection from the outerend of said casing, a longitudinally slidable pull-plate behind and in longitudinal alignment withsaid latch plate, said pull plate having spacedy rearwardly extending legs to straddle said cam-piece, each said leg having means engageable by the latter whereby to impart retractive movement to said pull-plate, a.

`compression spring footed against the rearward end of the casing for thrustingly engaging each said leg for yieldably retaining said pull-plate in forwardly moved normal position, and means intermediate said pull-plate and said latch plate for transmitting movements of the'former to the latter. v

4. In a door latch mechanism. a cylindrical casing adapted to be mortised into the free marginal edge portion of a door to be servedr by said latch mechanism, a cam-piece rotatively' mounted across said casing for operative engagement by door knob spindle means, a' spring projected latch plate longitudinally slidable in said casing and provided with a latch nose for projection from the outer end of said casing, a longitudinally slidable pull-plate behind and in longitudinal alignment with said latch plate, said pull plate having spaced rearwardly extending legs to straddle said cam-piece, each said leg having means engageable by the latter whereby to impart retractive movement to said pull-plate, a compression spring footed againts the rearward end of the casing for thrustingly engaging each said leg for yieldably retaining said pull-plate in forwardly moved normal position, and means intermediate said pull-plate and said latch plate for transmitting movements of the former to the latter, said latter means comprising a pivoted lever arm, a retractor means on said latch plate engageable by the free end portion of said lever arm, and means carried by said pull-plate to engage said lever arm intermediate its pivoted and outer free end portions.

` FRED KAISER. 

